Stretchable IR metamaterial with ultra-narrowband perfect absorption

The integration of a high-performance metamaterial (MM) onto mechanically flexible and deformable substrates offers significant promise in flexible electronics. Here, we propose two types of stretchable infrared (IR) MMs to design a tunable perfect absorber with a ring-shape (PA-RS) and a cross-shape (PA-CS) on a PDMS/Au/PDMS substrate, respectively. By stretching devices along different directions, PA-RS and PA-CS exhibit ultra-narrowband, polarization-dependent/independent, and switchable characterizations in the IR wavelength range. The tuning ranges are 2.37 μm and 2.36 μm for PA-RS and PA-CS with the deformation quantity of 2.50 μm along two-dimensional directions, respectively, without extra power supply. In this deformation range, most of the incident light is perfectly absorbed for PA-RS design operated at a wavelength of 4.31 μm and PA-CS design operated at a wavelength of 4.24 μm. The corresponding Q-factors of two devices are 98 and 118 for PA-RS and PA-CS, respectively. Such results are very suitable for high-performance refractive index sensor applications. Furthermore, two devices exhibit the functionalities of s-polarization switches and s-/p-polarization switches. To further investigate the characterizations of devices deformed by a tensile force, PA-CS could be actively tuned by bending devices at a certain angle. In the future, these proposed stretchable IR MMs could potentially possess high portability, applicability, and cost-effectiveness for wearable electronic devices in a variety of sensor fields.